Aristocraft Railbus

[MR SPOCK]

I have volunteered a task to see why my mates railbus is not a very good runner,​

On testing with the meter there is no continuity from the wheels on the motor truck to the metal chassis,which is split frame,I did read somewhere that Aristo were fitting roller bearings to there models, but these bearings are being made of ceramic , are they being fitted to this model as well as I can see no other reason for it not to work,
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[Rhinochugger]

Don't know the railbus block, but I have one of the earlier C16 8-coupled bricks.
The method of current continuity from steel rim on plastic wheel, is via a copper tanged washer, the tang slipping under the rim, and the washer section touching the bearing. Sometimes after wheel removal, the washer has to be tweaked at an angle to make effective contact.

 

[MR SPOCK]

I saw a tagged washer but the wheels are solid metal, I took the brick apart and found the wires to the plug are fixed into a tapped hole, even that was a poor continuity, the metal bearing outer ring had no circuit path to the axles, this is what makes me think that the rollers in the bearings are not metal,​

 

[Rhinochugger]

Does the washer have to touch the wheel and the block in some way?

My C16 runs with just the right amount of electrolube on the axles - not too little and not too much.

It also has the advantage of tender pickups

 

[Neil Robinson]

Pete, Greg Elmassian has done a fair bit of work on Aristo power blocks and his website makes interesting reading.
Below is a link to a relevant part of his site.
http://www.elmassian.com/trains-mai...r-mainmenu-72/prime-mover-basics-mainmenu-256 < Link To http://www.elmassian.com/...er-basics-mainmenu-256

 

[MR SPOCK]

thanks Neil, I think this was where I read about these bearings, will have a good read

 

[MR SPOCK]

hi Ian, the thing has definately no plastic or any pickups fitted, and looking at the bearing housings its designed like the bachman split chassis in OO scale, at the moment it is only picking up from the interesting front wheel arrangement, so stalling a lot, I will take some pics Sunday and see if a few hundered extra eyes can see what I am missing

Does the washer have to touch the wheel and the block in some way?

My C16 runs with just the right amount of electrolube on the axles - not too little and not too much.

It also has the advantage of tender pickups

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[ntpntpntp]

Hmm... I don't have one of these, but looking at the exploded diagram I don't see any obvious feed from the wheels to the motor.
http://www.aristocraft.com/techinfo/pdf/railbus.PDF

It does look like split chassis design similar to the c-16 block (I do have one of those). The C-16 block I have requires a plug to connect the chassis halves to the motor lugs, presumably to make some sort of provision for DCC. It won't go without being plugged in.

<edit>
George Schreyer's tips for the railbus indicates that it should pick up through the motor block wheels as well
http://www.girr.org/girr/tips/tips7/railbus_tips.html
</edit>

 

[MR SPOCK]

I took the whole drive unit apart to see what was going on and found two problems,the railbus was only picking up track power from the front wheels,these are very odd arangement but they were working fine,
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on further testing I found that the wires fitted to the block were not working either the wire had snapped inside or the crimping had been insulated by the sleeve, I removed the bits, so I could fit better later,​

I found the bearings on the axle shoulders and on removal and testing for electrical path found them to be a perfect insulator, I even tested them at 500volts, no good to get power from the wheels to the split block,​

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I then used some cunning and found four washers that were nice and thin, they fitted the axles and into the castings without any binding, that created a path, ​

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on reassembly the new plug and leads were fitted and the Railbus works a treat now, no stalling on any turnouts or wobbly track, ​

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Thanks everyone for the links and info,
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